Hard magnetic composition, permanent magnet powder, method for permanent magnet powder, and bonded magnet

A hard magnetic compound, characterized in that:

• the hard magnetic compound is represented by a general formula R11-uR2u (Fe100-y-wCowTiy)xSizAv(in the general formula, R1 is at least one element selected from rare earth elements (here, the rare earth elements signify a concept inclusive of Y), Nd accounts for 50 mol % or more of said R1, R2 is Zr and/or Hf and A is N and/or C);
• and
• the molar ratios in said general formula are such that u=0.18 or less, y=4.5 to 12.3, x=11 to 12.8, z=0.1 to 2.3, v=0.1 to 3 and w=0 to 30, and the relation (Fe+Co+Ti+Si)/(R1+R2)>12 is satisfied;
• wherein
• said hard magnetic compound shows a single phase consisting of a phase having a ThMn12-type structure.

A permanent magnet powder, characterized in that:

• the composition of the permanent magnet powder is represented by a general formula R(Fe100-y-wCowTiy)xSizAv (in the general formula, R is at least one element selected from rare earth elements (here the rare earth elements signify a concept inclusive of Y), Nd accounts for 50 mol% or more of said R, and A is N and/or C);
• the molar ratios in said general formula are such that x=10 to 12.8, y=(8.3−1.7×z) to 12.3, z=0.1 to 2.3, v=0.1 to 3 and w=0 to 30, and the relation (Fe+Co+Ti+Si)/R>12 is satisfied;
• the mean crystal grain size of the permanent magnet powder particles is 200 nm or less;
• and
• said articles show a single phase consisting of a phase substantially having a ThMn12-type structure.

A method for producing a permanent magnet powder, characterized by comprising the steps of:

• producing a powder by quenching and solidification of a melt of alloy wherein:
• the composition of the powder is represented by a general formula R(Fe100-y-wCowTiy)xSiz(in the general formula, R is at least one element selected from rare earth elements (here the rare earth elements signify a concept inclusive of Y), Nd accounts for 50 mol% or more of said R);
• and
• the molar ratios in said general formula are such that x=10 to 12.8, y=(8.3 −1.7×z) to 12.3, z=0.1 to 2.3 and w=0 to 30, and the relation (Fe+Co+Ti+Si)/R>12 is satisfied;
• heat-treating said powder so that the powder is maintained in an inert atmosphere at 650 to 850° C. for 0.5 to 120 hours;
• and
• nitriding or carbiding said heat-treated powder.

A bonded magnet comprising a permanent magnet powder and a resin phase to bind said permanent magnet powder, characterized in that:

• the composition of the crystalline hard magnetic particles constituting said permanent magnet powder is represented by a general formula R(Fe100-y-wCowTiy)xSizAv (in the general formula, R is at least one element selected from rare earth elements (here the rare earth elements signify a concept inclusive of Y), Nd accounts for 50 mol% or more of said R, and A is N and/or C);
• the molar ratios in said general formula are such that x=10 to 12.8, y=(8.3 −1.7×z) to 12.3, z=0.1 to 2.3, v=0.1 and w=0 to 30, and the relation (Fe+Co+Ti+Si)/R>12 is satisfied;
• and
• the articles of said permanent magnet powder show a single phase consisting of a phase substantially having the ThMn12-type structure.